A shift register is used for providing driving signals for gate lines and includes a plurality of shift register units arranged at a plurality of stages.
FIG. 1A is a schematic structure diagram of a shift register unit in the prior art, and FIG. 1B is a timing sequence diagram of the shift register unit shown in FIG. 1A. As shown in FIG. 1A, the shift register unit includes 12 thin film transistors (TFTs) and a storage capacitor, and a shift register constituted by the shift register units can only achieve a forward scanning driving instead of a bi-directional scanning driving.